diff --git a/README.md b/README.md
index 0d8bf6e..d3e59a2 100644
--- a/README.md
+++ b/README.md
@@ -700,7 +700,7 @@ C7:void foundReaderInfo(Reader* reader);\\查询读者信息
 C8:Reader* LendBook(Reader* reader, Book* book);\\读者借书
 ![888](LendBook.svg)
 C9:void returnBook(Reader* reader, Book* book);\\读者还书
-
+![999](returnBook.svg)
 C10:void save(Book* book);\\文件保存
 
 C11:Book* read1();\\从文件读取
diff --git a/returnBook.svg b/returnBook.svg
new file mode 100644
index 0000000..694b1f2
--- /dev/null
+++ b/returnBook.svg
@@ -0,0 +1,234 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created by Flowgorithm 3.4.2 (http://flowgorithm.org) -->
+
+<svg xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg" version="1.1" width="4284" height="6408">
+	<rect x="0" y="0" width="4284" height="6408" fill="#FFFFFF"/>
+	<g>
+		<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,360 648,447"/>
+		<polygon fill="#404040" stroke="none" points="648,468 668,433 627,433"/>
+		<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,6012 648,6099"/>
+		<polygon fill="#404040" stroke="none" points="648,6120 668,6085 627,6085"/>
+		<g>
+			<path fill="#F0E0FF" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" d="M 468,144 A 108 108, 0, 0 0, 468 360 L 828,360 A 108 108, 0, 0 0, 828 144 Z"/>
+			<text x="648" y="165" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+				<tspan x="648" dy="72" unicode-bidi="embed">returnBook</tspan>
+				<tspan x="648" dy="72" unicode-bidi="embed">(&#25972;&#25968;&#20540; id)</tspan>
+			</text>
+		</g>
+		<g>
+			<path fill="#F0E0FF" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" d="M 504,6120 A 72 72, 0, 0 0, 504 6264 L 792,6264 A 72 72, 0, 0 0, 792 6120 Z"/>
+			<text x="648" y="6141" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+				<tspan x="648" dy="72" unicode-bidi="embed">&#32467;&#26463;</tspan>
+			</text>
+		</g>
+		<g>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,648 648,735"/>
+			<polygon fill="#404040" stroke="none" points="648,756 668,721 627,721"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,936 648,1023"/>
+			<polygon fill="#404040" stroke="none" points="648,1044 668,1009 627,1009"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,1188 648,1275"/>
+			<polygon fill="#404040" stroke="none" points="648,1296 668,1261 627,1261"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,1440 648,1527"/>
+			<polygon fill="#404040" stroke="none" points="648,1548 668,1513 627,1513"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,5256 648,5343"/>
+			<polygon fill="#404040" stroke="none" points="648,5364 668,5329 627,5329"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,5508 648,5595"/>
+			<polygon fill="#404040" stroke="none" points="648,5616 668,5581 627,5581"/>
+			<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="648,5760 648,5847"/>
+			<polygon fill="#404040" stroke="none" points="648,5868 668,5833 627,5833"/>
+			<g>
+				<path fill="#FFFFD0" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" d="M 396,468 L 396,648 L 900,648 L 900,468 Z"/>
+				<polyline fill="none" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" points="396,504 900,504"/>
+				<polyline fill="none" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" points="432,468 432,648"/>
+				<text x="666" y="525" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="666" dy="72" unicode-bidi="embed">&#25972;&#25968;&#20540; reader</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#FFFFD0" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" d="M 432,756 L 432,936 L 864,936 L 864,756 Z"/>
+				<polyline fill="none" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" points="432,792 864,792"/>
+				<polyline fill="none" stroke="#A0A070" stroke-width="5" stroke-dasharray="none" points="468,756 468,936"/>
+				<text x="666" y="813" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="666" dy="72" unicode-bidi="embed">&#25972;&#25968;&#20540; id</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#C0E0FF" stroke="#6080A0" stroke-width="5" stroke-dasharray="none" d="M 504,1044 L 432,1188 L 792,1188 L 864,1044 Z"/>
+				<text x="648" y="1065" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="648" dy="72" unicode-bidi="embed">&#36755;&#20837; id</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#F0E0FF" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" d="M 432,1296 L 432,1440 L 864,1440 L 864,1296 Z"/>
+				<polyline fill="none" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" points="468,1296 468,1440"/>
+				<polyline fill="none" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" points="828,1296 828,1440"/>
+				<text x="648" y="1317" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="648" dy="72" unicode-bidi="embed">getchar()</tspan>
+				</text>
+			</g>
+			<g>
+				<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="936,1728 1116,1728 1116,1995"/>
+				<polygon fill="#404040" stroke="none" points="1116,2016 1136,1981 1095,1981"/>
+				<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="1116,2160 1116,5220 704,5220"/>
+				<polygon fill="#404040" stroke="none" points="684,5220 718,5240 718,5199"/>
+				<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="360,1728 180,1728 180,5220 591,5220"/>
+				<polygon fill="#404040" stroke="none" points="612,5220 577,5199 577,5240"/>
+				<g>
+					<path fill="#FFD0D0" stroke="#A07070" stroke-width="5" stroke-dasharray="none" d="M 648,1548 L 324,1728 L 648,1908 L 972,1728 Z"/>
+					<text x="648" y="1677" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+						<tspan x="648" dy="72" unicode-bidi="embed">reader!=NULL</tspan>
+					</text>
+				</g>
+				<g>
+					<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="1476,2088 1908,2088 1908,2211"/>
+					<polygon fill="#404040" stroke="none" points="1908,2232 1928,2197 1887,2197"/>
+					<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="1908,4932 1908,5040 1188,5040 1188,2180"/>
+					<polygon fill="#404040" stroke="none" points="1188,2160 1167,2194 1208,2194"/>
+					<g>
+						<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2268,2448 2448,2448 2448,2715"/>
+						<polygon fill="#404040" stroke="none" points="2448,2736 2468,2701 2427,2701"/>
+						<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2448,3456 2448,4896 1964,4896"/>
+						<polygon fill="#404040" stroke="none" points="1944,4896 1978,4916 1978,4875"/>
+						<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="1548,2448 1368,2448 1368,4896 1851,4896"/>
+						<polygon fill="#404040" stroke="none" points="1872,4896 1837,4875 1837,4916"/>
+						<g>
+							<path fill="#C04040" stroke="#602020" stroke-width="5" stroke-dasharray="none" d="M 1908,2232 L 1512,2448 L 1908,2664 L 2304,2448 Z"/>
+							<text x="1908" y="2397" fill="#FFFFFF" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+								<tspan x="1908" dy="72" unicode-bidi="embed">id == reader-&gt;iNum</tspan>
+							</text>
+						</g>
+						<g>
+							<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2448,2916 2448,3003"/>
+							<polygon fill="#404040" stroke="none" points="2448,3024 2468,2989 2427,2989"/>
+							<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2448,3168 2448,3291"/>
+							<polygon fill="#404040" stroke="none" points="2448,3312 2468,3277 2427,3277"/>
+							<g>
+								<path fill="#C04040" stroke="#602020" stroke-width="5" stroke-dasharray="none" d="M 2160,2736 L 2160,2916 L 2736,2916 L 2736,2736 Z"/>
+								<polyline fill="none" stroke="#602020" stroke-width="5" stroke-dasharray="none" points="2160,2772 2736,2772"/>
+								<polyline fill="none" stroke="#602020" stroke-width="5" stroke-dasharray="none" points="2196,2736 2196,2916"/>
+								<text x="2466" y="2793" fill="#FFFFFF" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+									<tspan x="2466" dy="72" unicode-bidi="embed">&#25972;&#25968;&#20540; id_book</tspan>
+								</text>
+							</g>
+							<g>
+								<path fill="#C04040" stroke="#602020" stroke-width="5" stroke-dasharray="none" d="M 2196,3024 L 2124,3168 L 2700,3168 L 2772,3024 Z"/>
+								<text x="2448" y="3045" fill="#FFFFFF" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+									<tspan x="2448" dy="72" unicode-bidi="embed">&#36755;&#20837; id_book</tspan>
+								</text>
+							</g>
+							<g>
+								<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2880,3384 3240,3384 3240,3507"/>
+								<polygon fill="#404040" stroke="none" points="3240,3528 3260,3493 3219,3493"/>
+								<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="3240,4608 3240,4716 2520,4716 2520,3476"/>
+								<polygon fill="#404040" stroke="none" points="2520,3456 2499,3490 2540,3490"/>
+								<g>
+									<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="3600,3744 3780,3744 3780,4047"/>
+									<polygon fill="#404040" stroke="none" points="3780,4068 3800,4033 3759,4033"/>
+									<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="3780,4212 3780,4572 3296,4572"/>
+									<polygon fill="#404040" stroke="none" points="3276,4572 3310,4592 3310,4551"/>
+									<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="2880,3744 2700,3744 2700,4572 3183,4572"/>
+									<polygon fill="#404040" stroke="none" points="3204,4572 3169,4551 3169,4592"/>
+									<g>
+										<path fill="#C04040" stroke="#602020" stroke-width="5" stroke-dasharray="none" d="M 3240,3528 L 2844,3744 L 3240,3960 L 3636,3744 Z"/>
+										<text x="3240" y="3693" fill="#FFFFFF" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+											<tspan x="3240" dy="72" unicode-bidi="embed">reader-&gt;aiBookId[i]</tspan>
+										</text>
+									</g>
+									<g>
+										<polyline fill="none" stroke="#404040" stroke-width="9" stroke-dasharray="none" points="3996,4140 4104,4140 4104,4392 3852,4392 3852,4232"/>
+										<polygon fill="#404040" stroke="none" points="3852,4212 3831,4246 3872,4246"/>
+										<g>
+										</g>
+										<g>
+											<path fill="#FFE0A0" stroke="#A08040" stroke-width="5" stroke-dasharray="none" d="M 3636,4068 L 3564,4140 L 3636,4212 L 3924,4212 L 3996,4140 L 3924,4068 Z"/>
+											<text x="3780" y="4089" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+												<tspan x="3780" dy="72" unicode-bidi="embed">book</tspan>
+											</text>
+										</g>
+										<text x="4068" y="4017" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+											<tspan x="4068" dy="72" unicode-bidi="embed">&#30495;</tspan>
+										</text>
+										<text x="3708" y="4233" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+											<tspan x="3708" dy="72" unicode-bidi="embed">&#20551;</tspan>
+										</text>
+									</g>
+									<g>
+									</g>
+									<ellipse cx="3240" cy="4572" rx="36" ry="36" fill="#C04040" stroke="#602020" stroke-width="5"/>
+									<text x="3708" y="3621" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+										<tspan x="3708" dy="72" unicode-bidi="embed">&#30495;</tspan>
+									</text>
+									<text x="2772" y="3621" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+										<tspan x="2772" dy="72" unicode-bidi="embed">&#20551;</tspan>
+									</text>
+								</g>
+								<g>
+									<path fill="#C04040" stroke="#602020" stroke-width="5" stroke-dasharray="none" d="M 2088,3312 L 2016,3384 L 2088,3456 L 2808,3456 L 2880,3384 L 2808,3312 Z"/>
+									<text x="2448" y="3333" fill="#FFFFFF" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+										<tspan x="2448" dy="72" unicode-bidi="embed">i = 0 &#21040; reader-&gt;iMax</tspan>
+									</text>
+								</g>
+								<text x="3024" y="3261" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+									<tspan x="3024" dy="72" unicode-bidi="embed">&#19979;&#19968;&#20010;</tspan>
+								</text>
+								<text x="2340" y="3477" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+									<tspan x="2340" dy="72" unicode-bidi="embed">&#23436;&#25104;</tspan>
+								</text>
+							</g>
+						</g>
+						<g>
+						</g>
+						<ellipse cx="1908" cy="4896" rx="36" ry="36" fill="#C04040" stroke="#602020" stroke-width="5"/>
+						<text x="2376" y="2325" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+							<tspan x="2376" dy="72" unicode-bidi="embed">&#30495;</tspan>
+						</text>
+						<text x="1440" y="2325" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+							<tspan x="1440" dy="72" unicode-bidi="embed">&#20551;</tspan>
+						</text>
+					</g>
+					<g>
+						<path fill="#FFE0A0" stroke="#A08040" stroke-width="5" stroke-dasharray="none" d="M 828,2016 L 756,2088 L 828,2160 L 1404,2160 L 1476,2088 L 1404,2016 Z"/>
+						<text x="1116" y="2037" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+							<tspan x="1116" dy="72" unicode-bidi="embed">reader != NULL</tspan>
+						</text>
+					</g>
+					<text x="1548" y="1965" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+						<tspan x="1548" dy="72" unicode-bidi="embed">&#30495;</tspan>
+					</text>
+					<text x="1044" y="2181" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+						<tspan x="1044" dy="72" unicode-bidi="embed">&#20551;</tspan>
+					</text>
+				</g>
+				<g>
+				</g>
+				<ellipse cx="648" cy="5220" rx="36" ry="36" fill="#FFD0D0" stroke="#A07070" stroke-width="5"/>
+				<text x="1044" y="1605" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="1044" dy="72" unicode-bidi="embed">&#30495;</tspan>
+				</text>
+				<text x="252" y="1605" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="252" dy="72" unicode-bidi="embed">&#20551;</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#E0E0E0" stroke="#505050" stroke-width="5" stroke-dasharray="none" d="M 504,5364 L 432,5508 L 792,5508 L 864,5364 Z"/>
+				<text x="648" y="5385" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="648" dy="72" unicode-bidi="embed">&#36755;&#20986;</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#E0E0E0" stroke="#505050" stroke-width="5" stroke-dasharray="none" d="M 504,5616 L 432,5760 L 792,5760 L 864,5616 Z"/>
+				<text x="648" y="5637" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="648" dy="72" unicode-bidi="embed">&#36755;&#20986;</tspan>
+				</text>
+			</g>
+			<g>
+				<path fill="#F0E0FF" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" d="M 432,5868 L 432,6012 L 864,6012 L 864,5868 Z"/>
+				<polyline fill="none" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" points="468,5868 468,6012"/>
+				<polyline fill="none" stroke="#9070A0" stroke-width="5" stroke-dasharray="none" points="828,5868 828,6012"/>
+				<text x="648" y="5889" fill="#000000" font-family="Arial" font-size="32pt" text-anchor="middle" direction="ltr">
+					<tspan x="648" dy="72" unicode-bidi="embed">getchar()</tspan>
+				</text>
+			</g>
+		</g>
+	</g>
+</svg>