字符串连接 strcmp#include 
     
      void main(){   char c1[] = "Hello ", c2[]="WORLD", c3[13];  int i,j,k;  i=j=k=0;  while(c1[i] != '\0' || c1[j] != '\0'){      if(c1[i] != '\0'){          c3[k] = c1[i++];      }else{          c3[k] = c2[j++];      }      k++;  }  c3[k]= '\0';  puts(c3);}
     

 杨辉三角

#include 
     
      void main(){   int i,j,test[10][10];  for(i=0;i<10;i++){      test[i][0] = 1;      test[i][i] = 1;  }    for(i=2;i<10;i++){      for(j=1;j