diff --git a/3.c b/3.c
new file mode 100644
index 0000000..498205d
--- /dev/null
+++ b/3.c
@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctime>
+#include <iostream>
+#include <ostream>
+#define SIZE 1024
+int main(){
+	void matmul(float **A,float **B,float **C,int n);
+	int i,j,n;
+	float **A=new float*[n];
+	float **B=new float*[n];
+	float **C=new float*[n];
+	for(i=0;i<n;i++){
+		A[i]=new float[n];
+		B[i]=new float[n];
+		C[i]=new float[n];
+	}
+	for(i=0;i<n;i++){
+		for(j=0;j<n;j++){
+			A[i][j]=rand()%100;
+			B[i][j]=rand()%100;
+		}
+	}
+	clock_t start=clock();
+	matmul(A,B,C,SIZE);
+	clock_t end=clock();
+    std::cout<<"»ù´¡³íÃܾØÕó³Ë·¨Ê±¼ä£º"<<double(end-start)/CLOCKS_PER_SEC<<"Ãë"<<std::endl; 
+	for(i=0;i<n;i++){
+		delete[] A[i];
+		delete[] B[i];
+		delete[] C[i];
+	}
+	delete[] A;
+	delete[] B;
+	delete[] C;
+}
+void matmul(float **A,float **B,float **C,int n){
+	int i,j,k;
+	for(i=0;i<n;i++){
+		for(j=0;j<n;j++){
+			C[i][j]=0;
+			for(k=0;k<n;k++){
+				C[i][j]=C[i][j]+A[i][k]*B[k][j];
+			}
+		}
+	}
+}
+