pawn function to check a date is valid or not with any possible format.

isValidDate.pwn

bool:isValidDate(str[])//by Sreyas 
{ 
    new count,i,j; 
    new daysinmonth[12]={31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 
    new parts[3][5],Index_Beg; 
    new bool:legit; 

    while(str[i]!='\0') 
    { 
        if(str[i] < 48 || str[i] > 57) 
        { 
            count++; 
            strmid(parts[j], str, Index_Beg, i, sizeof(parts[])); 
            Index_Beg = i+1; 
            j++; 

        } 
        i++; 

        if(str[i]=='\0') 
        { 

            strmid(parts[j], str, Index_Beg, i, sizeof(parts[])); 

        } 
    } 


    if(count != 2) return false; 

    new number[3]; 

    for(i=0;i<3;i++) 
    { 
        number[i] = strval(parts[i]); 
        if(number[i] == 0)return false; 
    } 

    new y,m,d; 

    y = m = d = -1; 


    for(i=0;i<3;i++) 
    { 
        if(number[i]>31) 
        { 

            if(y != -1) return false; 
            y = i; 

        } 
    } 
    for(i=0;i<3;i++) 
    { 
        if(i == y) continue; 

        if(number[i] < 13 && number[i] > 0) 
        { 
            if(m == -1) 
            { 
                m = i; 
            } 
            else 
            { 
                d = i; 

            } 
        } 
    } 


    if(y==-1) 
    { 
        for(i=0;i<3;i++) 
        { 
            if(i==d||i==m) continue; 
            y = i; 

        } 
    } 

    if(d==-1) 
    { 
        for(i=0;i<3;i++) 
        { 
            if(i==y||i==m) continue; 
            d = i; 

        } 
    } 
     
    if(m==-1) 
    { 
        for(i=0;i<3;i++) 
        { 
            if(i==y||i==d) continue; 
            m = i; 

        } 
    } 
     

    if(number[y] % 400 == 0 || (number[y] % 100 != 0 && number[y] % 4 == 0)) 
        daysinmonth[1]=29; 

    if( number[m]<13 && number[d] <= daysinmonth[number[m]-1]) 
        legit=true; 


    if (!legit) return false; 

    return true; 

}