expected integer but got "floating point number" error

Question

I try to write a very simple program in TCL using list.

Below is the list

list { 1 2 3 4 5 6 1.5 7 }

Below is my code

set sum 0
for {set i 0} {$i < [llength $list]} {incr i} {
    incr sum [lindex $list $i]
}

puts  $sum

On executing the above program I am getting the below error due to floating point value of 1.5 in the list

expected integer but got "1.5"
    (reading increment)
    invoked from within
"incr sum [lindex $list $i]"

I searched on internet and could not find anything relevant. Please advise how do I handle the floating point value?

Answer 1

While using incr command, variable must have value that can be interpreted as a an integer. See tcl wiki. If variable is a non-integral real number, [incr] could not be used, but [set] could:

set sum 0
for {set i 0} {$i < [llength $list]} {incr i} {
    set sum [expr {$sum + [lindex $list $i]}]
}

puts  $sum