[Dev-C++] The strange action of getchar( ).

[<per...@ya...>]

My program is list belove:
/*  *********************************************** */
#include <stdio.h>
#define MAXVEX    8
main()
{
    char ga[MAXVEX];
    int i, v1, v2, vexnum, edgenum;
    
    
    printf("Input the number of vertex:");
    scanf("%d", &vexnum);
    getchar(); /* sentence 1 */
    printf("Input the information of vertex:");
    for (i = 1; i <= vexnum; i++) {
        ga[i] = getchar();
    }
    printf("Input the number of edge:");    
    scanf("%d", &edgenum); /* sentence 2 */
    printf("The pair of the vertvex in the edge:");
    for (i = 1; i <= edgenum; i++) {
        scanf("%d%d", &v1, &v2);  /* sentence 3 */     
    } 
    system("PAUSE");
}
/* ****************************************** */
     If I remove the sentence 1 from the program.The result is list here:
 
/* *********result 1************************ */
Input the number of vertex:2
Input the information of vertex:ab
Input the number of edge:The pair of the vertvex in the edge:
/* ********************************* */
 
      It seem that the sentence 2 and 3 are not executed.If I put  the sentence 1 to the original place,the program is result this:
 
/* ************result 2********************* */
Input the number of vertex:2
Input the information of vertex:ab
Input the number of edge:1
The pair of the vertvex in the edge:1 2
Please press any key to continue...
/* ********************************* */
 
   This result 2  I think it it is right.Is it the problem caused by the first getchar( ) where is sentence 1? Why I remove the sentence 1 will bring the issue?Up to now I still don't know why.
    Thanks,
    Bruce .J  Sam

 
 
 
 
   
 



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