Identidad

 #include <stdio.h>
 
 
 
 	int main(){
 	
 	int matriz[4][4]={{1,0,0,0},{0,1,0,0},{0,0,1,0},{0,0,0,1}};
 		int ren, col;
 		for(ren=0; col<4; ren++){
 			for(col=0; col<4; col++){
 				if(ren==col);
				 printf("1");
				else
				 printf("0");
 			}
 				printf("\n");
 		}
 			return 0;
 		}